S12.391A vs S12.391B

S12.391A (Other nondisplaced fracture of fourth cervical vertebra, initial encounter for closed fracture) compared with S12.391B (Other nondisplaced fracture of fourth cervical vertebra, initial encounter for open fracture), from the official CMS tabular data. S12.391A and S12.391B code the same injury at a different phase of treatment.

Relationship

Review

Encounter relationship

S12.391A

Initial encounter

Other nondisplaced fracture of fourth cervical vertebra, initial encounter for closed fracture

↔

S12.391B

Initial encounter

Other nondisplaced fracture of fourth cervical vertebra, initial encounter for open fracture

Same underlying diagnosis, different encounter phase.

The 7th character records the phase of care for the encounter being coded, so a single encounter takes one of these characters, not several. Review whether both phases belong on the same episode of care.

Source: ICD-10-CM Official Guidelines, Section I.C.19.a

Can these codes be reported together?

Same injury, other encounter phase. S12.391A and S12.391B code the same injury at a different phase of treatment, set by the 7th character.

The 7th character records the type of care given at the encounter being coded (ICD-10-CM Official Guidelines, Section I.C.19.a), so one encounter takes one of these, not both.

Side by side

	S12.391AOther nondisplaced fracture of fourth cervical vertebra, initial encounter for closed fracture	S12.391BOther nondisplaced fracture of fourth cervical vertebra, initial encounter for open fracture
Billing status	Billable	Billable
Classification	S00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88)	S00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88)
Definition	Other nondisplaced fracture of fourth cervical vertebra, initial encounter for closed fracture is a billable ICD-10-CM diagnosis code (S12.391A).	Other nondisplaced fracture of fourth cervical vertebra, initial encounter for open fracture is a billable ICD-10-CM diagnosis code (S12.391B).
7th character	The appropriate 7th character is to be added to all codes from subcategories S12.0-S12.6	The appropriate 7th character is to be added to all codes from subcategories S12.0-S12.6
Includes	fracture of cervical neural arch fracture of cervical spine fracture of cervical spinous process fracture of cervical transverse process	fracture of cervical neural arch fracture of cervical spine fracture of cervical spinous process fracture of cervical transverse process
Code first	any associated cervical spinal cord injury (S14.0, S14.1-)	any associated cervical spinal cord injury (S14.0, S14.1-)

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Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources